Method and device for detecting a collision and delimiting it with respect to normal vehicle operation

ABSTRACT

A method for detecting a collision of a vehicle, using a measuring device rigidly connected to the vehicle, including the following features: —in each instance, an acceleration of the measuring device with regard to a plurality of device coordinate axes specific to the measuring device is measured; in each instance, an installation position angle of the measuring device with respect to a plurality of vehicle coordinate axes specific to the vehicle is calculated and/or measured and/or programmed from outside; with the aid of the installation position angles, a vehicle acceleration along the vehicle coordinate axes is ascertained, and an evaluation of the accelerations is undertaken; and the degree of determination of the installation position is ascertained by the device and taken into consideration for weighting the accelerations. the collision is detected in light of the evaluation of the vehicle acceleration.

FIELD

The present invention relates to a method for detecting a collision. In addition, the present invention relates to a corresponding telematics unit, as well as to a corresponding computer program, storage medium and vehicle.

BACKGROUND INFORMATION

So-called crash or impact sensors, which are used in motor vehicles in order to detect various collisions of the vehicle in question, are sufficiently well-known in the area of vehicle safety. For example, in response to a considerable shock, a stationary-mounted measuring device transmits an electrical impulse via the bus of the specific vehicle, to various other control units, which are able, in turn, to activate different occupant protection systems. To this end, depending on the level of standard equipment, these may include, for instance, airbags, seat-belt force limiters, belt tensioners and roll bars of the vehicle. In this context, crash sensors of a simple type of construction detect only the damaging event, as such, and activate the above-mentioned occupant protection systems as soon as a predefined threshold value of the vehicle deceleration is exceeded, while more progressive measuring devices are also able to detect the severity of the impact.

The related art also includes stationary-mounted or retrofittable telematics units for motor vehicles, which include such sensor technology and automatically transmit, for example, to a vehicle fleet operator or vehicle fleet.

For example, German Patent Application No. DE 10138764 describes a set-up for detecting a head-on collision in a vehicle, where at least one upfront sensor is used as plausibility sensor, which supplies a plausibility signal for a crash sensor located in the control unit. The upfront sensor is an acceleration sensor, which checks both the acceleration signal and the speed signal derived from it for plausibility. The results of this check are linked in an OR-operation, in order to generate a plausibility signal. In one further refinement, it is provided that the plausibility signal be stored in the control unit for a predetermined time. This is of interest, in particular, for increasing a margin of safety in the event that the upfront sensor has been destroyed.

SUMMARY

The present invention provides a method for detecting a collision of a vehicle, a corresponding telematics unit, as well as a corresponding computer program, storage medium and vehicle.

In this connection, the approach of the present invention is based on the realization that in the case of conventional measuring devices, the acceleration values with respect to the device coordinate axes are evaluated mostly without regard to the installation position of the device. However, one specific embodiment of the present invention considers three aspects: first, during operation of a road vehicle, marked accelerations, which are caused by potholes, occasionally occur in its yaw, normal or vertical axis (z). Secondly, with regard to driving dynamics, serious accidents typically take place in the plane (x-y) spanned by the roll or longitudinal axis (x) and the pitch or transverse axis (y) of the vehicle. Thirdly and finally, collisions in the lateral region of the vehicle, which are characterized by an acceleration along the pitch axis, are particularly dangerous for its occupants.

Accordingly, one advantage of the telematics unit in accordance with the present invention already lies in the advantageous detection and evaluation of vehicle-specific accelerations in the case of rough position detection of the telematics unit. In this manner, one preferred specific embodiment of the present invention allows it to detect crashes without being connected to the vehicle bus system.

Thus, a telematics unit of the present invention allows the acceleration values to be evaluated accurately without the exact position of the unit having to be known beforehand via information on this matter on the part of its operator, or without a software input by the operator and/or manufacturer having to take place.

If an accident is detected by a telematics unit of the present invention, then, for example, an emergency call may be sent by the telematics unit. To that end, the telematics unit includes a communications device for contacting an emergency service center. The communications unit may be connected to an emergency service center via a wireless connection in the form a stationary processing unit (computer) or mobile processing unit (e.g., cellular phone, tablet). In this case, the exchange of data with the emergency service center takes place, for example, via WLAN, wireless mobile radio communication technology, or Bluetooth. The telematics unit detects an accident, if a collision is identified in light of the evaluation of the vehicle acceleration.

Advantageous further refinements of and improvements to the root idea of the present invention are made possible by the measures described herein. Thus, it may be provided that the weighting of the acceleration correlate with the quality of the installation position. This embodiment allows the telematics unit to distinguish more effectively between crash events and other disturbances, such as potholes, independently of the position and installation location in the vehicle; the potholes being encountered, for example, during dynamic travel over a rough road.

For example, in response to a considerable shock, a stationary-mounted measuring device transmits an electrical impulse via the bus of the specific vehicle, to various other control units, which are able, in turn, to activate different occupant protection systems.

According to one further aspect, the weighting of the acceleration along the transverse axis may also be applied as a function of the quality of the position. Such a specific embodiment allows the potential danger to occupants to be estimated more effectively, independently of the position and the installation location in the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention are represented in the figures and explained in greater detail in the following description.

FIG. 1 shows the activity diagram of a method according to a first specific embodiment of the present invention.

FIG. 2 shows the perspective view of a road vehicle according to a second specific embodiment.

FIG. 3 shows a graph of a function.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 illustrates the basic steps of a method 10 of the present invention for collision detection in a vehicle 25; the steps now being explained in light of the application case depicted in FIG. 2. In this case, method 10 is executed by a retrofitted telematics unit 20 of vehicle 25 without a connection to its bus system, which is not shown graphically. However, a corresponding method 10 may also be implemented in a stationary-mounted control unit or other measuring device (20), for example, by software or hardware or a mixture of software and hardware, without departing from the scope of the present invention.

To this end, telematics unit 20 periodically measures its acceleration with respect to its own device coordinate axes (X, Y, Z) in an initially conventional manner (actions 11, 12, 13). Appropriate detecting elements in the form of acceleration sensors, accelerometers, or G-sensors are familiar to one skilled in the art. In addition, telematics unit (20) detects its installation position (actions 14, 15, 16). Integrated gyroscope and acceleration sensors suitable for this purpose may be implemented, for example, in the form of microelectromechanical systems (MEMS). In this connection, the degree of determination of the installation position of device coordinates (X, Y, Z) with respect to vehicle coordinate system (x, y, z) determines, so to speak, the quality of the installation position, with the aid of which the sensitivity or responsivity of unit (20) to particular acceleration components may be adjusted. Consequently, the installation position angles (α, β, γ) determined in accordance with FIG. 2 constitute the relationship between device coordinates and vehicle coordinates.

Telematics unit 20 is now able to undertake a sophisticated evaluation of the accelerations as a function of the quality of the installation position (action 17). If a certain quality of the installation position (determined by quality coefficient GZ) is attained, then the weighting “takes effect” and effects a reduction or gain in the acceleration used as an input variable. Thus, there is the option of setting the weighting as a function of quality coefficient GZ.

To this end, telematics unit 20 ascertains the acceleration along each of the device coordinate axes (X, Y, Z) and relates them to vehicle coordinates (x, y, z) on the basis of the ascertained installation position angle. The weighting on the basis of quality coefficient GZ is then applied to the specific vehicle acceleration, which is then subsequently evaluated, using an algorithm. If, for example, unit (20) is mounted in vehicle 25 in a nearly upright position, then its vertical axis Z substantially corresponds to yaw axis z of vehicle 25; the two axes Z, z are at a comparatively small angle γ to each other. Therefore, since a Z-acceleration of telematics unit 20 is typically caused by potholes 24 or other irregularities of roadway 23, unit 20 henceforth reduces the weighting of this component and consequently “damps” its influence on the evaluation of the situation.

This continuous function g_(Z)(GZ) may be implemented with respect to a quality coefficient GZ; the quality coefficient being derived from the position determination. The quality coefficient correlates with the effect on the respective acceleration. The more accurately the position of the telematics unit is known, the stronger the affect is on the respective acceleration.

Since the z-axis of the vehicle may be ascertained rapidly from the acceleration due to gravity, this method is particularly suitable for the weighted evaluation of the z-axis of the vehicle. Thus, actual crash events may be distinguished more clearly from other disturbances, such as potholes.

FIG. 3 illustrates an example of the relationship g(z)=gz*dz, where dz=f(GZ). 

1-11. (canceled)
 12. A method for detecting a collision of a vehicle, using a measuring device rigidly connected to the vehicle, the method comprising: in each instance, measuring an acceleration of the measuring device relative to a plurality of device coordinate axes specific to the measuring device; in each instance, calculating, and/or measuring and/or programming from outside, an installation position angle of the measuring device with respect to a plurality of vehicle coordinate axes specific to the vehicle; ascertaining a vehicle acceleration along the vehicle coordinate axes using the installation position angles, and evaluating the accelerations; ascertaining a degree of determination of the installation position by the device and weighting the accelerations taking the ascertained degree into consideration; and detecting the collision in light of the evaluation of the vehicle acceleration.
 13. The method as recited in claim 12, wherein at least the accelerations are measured repeatedly.
 14. The method as recited in claim 12, wherein at least the accelerations are measured periodically.
 15. The method as recited in claim 12, wherein with regard to each device coordinate axis device coordinate axes, a weighting of the acceleration along the device coordinate axis is adjusted in light of the installation position angle or the quality coefficient; and wherein the evaluation of the accelerations is carried out as a function of their weightings.
 16. The method as recited in claim 15, wherein each device coordinate axis among the device coordinate axes is assigned a vehicle coordinate axis among the vehicle coordinate axes; and wherein the weighting of the acceleration along each vehicle coordinate axis is a continuous function of the installation position angle or a continuous function of the quality coefficient regarding the vehicle coordinate axis assigned to the device coordinate axis.
 17. The method as recited in claim 16, wherein the device coordinate axes include a vertical axis, the vehicle coordinate axes include a yaw axis, and the weighting of the acceleration along the vertical axis correlates with the installation position angle or the quality coefficient with regard to the yaw axis.
 18. The method as recited in claim 16, wherein the device coordinate axes include a transverse axis, the vehicle coordinate axes include a pitch axis, and the weighting of the acceleration along the transverse axis correlates with the installation position angle or the quality coefficient with regard to the pitch axis.
 19. The method as recited in claim 16, wherein the device coordinate axes include a longitudinal axis, the vehicle coordinate axes include a roll axis; and the weighting of the acceleration along the longitudinal axis correlates with the installation position angle or the quality coefficient with regard to the roll axis.
 20. A non-transitory machine-readable storage medium on which is stored a computer program for detecting a collision of a vehicle, using a measuring device rigidly connected to the vehicle, the computer program, when executed by a computer, causing the computer to perform: in each instance, measuring an acceleration of the measuring device relative to a plurality of device coordinate axes specific to the measuring device; in each instance, calculating, and/or measuring and/or programming from outside, an installation position angle of the measuring device with respect to a plurality of vehicle coordinate axes specific to the vehicle; ascertaining a vehicle acceleration along the vehicle coordinate axes using the installation position angles, and evaluating the accelerations; ascertaining a degree of determination of the installation position by the device and weighting the accelerations taking the ascertained degree into consideration; and detecting the collision in light of the evaluation of the vehicle acceleration.
 21. A telematics unit, which is configured to detect a collision of a vehicle, using a measuring device rigidly connected to the vehicle, the telematics unit configured to: in each instance, measure an acceleration of the measuring device relative to a plurality of device coordinate axes specific to the measuring device; in each instance, calculate, and/or measure and/or program from outside, an installation position angle of the measuring device with respect to a plurality of vehicle coordinate axes specific to the vehicle; ascertain a vehicle acceleration along the vehicle coordinate axes using the installation position angles, and evaluate the accelerations; ascertain a degree of determination of the installation position by the device and weight the accelerations taking the ascertained degree into consideration; and detect the collision in light of the evaluation of the vehicle acceleration.
 22. A vehicle having a telematics unit configured to detect a collision of a vehicle, using a measuring device rigidly connected to the vehicle, the telematics unit configured to: in each instance, measure an acceleration of the measuring device relative to a plurality of device coordinate axes specific to the measuring device; in each instance, calculate, and/or measure and/or program from outside, an installation position angle of the measuring device with respect to a plurality of vehicle coordinate axes specific to the vehicle; ascertain a vehicle acceleration along the vehicle coordinate axes using the installation position angles, and evaluate the accelerations; ascertain a degree of determination of the installation position by the device and weight the accelerations taking the ascertained degree into consideration; and detect the collision in light of the evaluation of the vehicle acceleration. 